1. Technical Field
The present invention relates to a sensor, a conveying device and an image forming apparatus.
2. Related Art
A plate-like or film-like optical filter has been known in the past.
When the presence or absence of a detection target is detected by a reflection-type light sensor, an optical filter causes condensation in certain temperatures and humidities of the surrounding environment if the optical filter is placed on the front side of a light emitting part or the light receiving part so that the presence of the detection target is not falsely detected by the light reflected and scattered by members or the like except for the detection target. For this reason, the optical filter may lose the function of a sensor.